Rosacea is a chronic inflammatory disorder of the central face characterized by persistent erythema, flushing, and inflammatory papules. Azelaic acid (Az) is a first-line topical therapy for papulopustular rosacea; however, its clinical efficacy is limited by poor aqueous solubility and restricted penetration across the stratum corneum. To overcome these limitations, PEGylated lipid-polymer hybrid nanoparticles (PALPHNs) encapsulating Az were developed and optimized using a Central Composite Design. The optimized PALPHNs exhibited a mean particle size of 179.6 ± 7.6 nm, narrow polydispersity (0.20 ± 0.03), stable zeta potential (-32.75 ± 1.4 mV), and high entrapment efficiency (92.13 ± 1.4%). Incorporation into a Carbopol hydrogel yielded a stable, skin-compatible formulation with physiological pH (5.84 ± 0.12). In vitro release studies demonstrated biphasic and sustained drug release, achieving 87.74 ± 0.002% cumulative release at 24 h compared with 72.21 ± 0.001% from conventional Az gel. Ex vivo permeation studies showed significantly enhanced Az penetration from the PALPHN gel (448.85 µg/cm²) vs the conventional gel (183.68 µg/cm²), with higher steady-state flux (18.21 vs 7.25 µg/cm²/h). Confocal laser scanning microscopy confirmed deeper epidermal penetration (∼44 µm). Safety assessment using HET-CAM and skin irritation studies showed good tolerability (PII = 0.875). In vivo evaluation using a croton oil-induced ear edema model demonstrated greater reduction in ear thickness (0.98 mm) compared with conventional Az gel (1.08 mm). Overall, the PALPHN hydrogel represents a promising nanocarrier system for topical rosacea therapy.
Salmani et al. (Thu,) studied this question.